The present invention relates to an image recording apparatus such as a copying machine or a printer, and more particularly, to a type thereof in which an elongated continuous web like sheet of photosensitive recording medium is easily changed with a new one. Further, related U.S. Patent Applications have been filed bearing Ser. Nos. 07/281,336 filed on Dec. 8, 1988 (corresponding to Japanese Utility Model application Ser. No. 62-189349) and 07/281,327 filed on Dec. 8, 1988 (corresponding to Japanese Utility Model application Ser. Nos. 62-189350, 62-191005 and 62-191013).
One conventional image recording apparatus or copying apparatus which employs the elongated photosensitive recording medium is shown in FIG. 1. In the apparatus, the recording medium is of transfer type recording medium such as a photosensitive sheet which comprises a microcapsule sheet 306 (first image recording medium) and a developer sheet 309 (second image recording medium). More specifically, in the transfer type recording mediums, the developer material is coated on a separate substrate as a separate developer or copy sheet. The first image recording medium comprises a photosensitive pressure sensitive recording medium provided with microcapsules which encapsulate therein a first material (chromogenic material or dye precursor) having first and second phases dependent on light exposure. The second image recording medium comprises the developer medium provided with a second material (developer material) which provides an output image upon reaction with the first material. Such image recording medium is disclosed in, for example, U.S. Pat. No. 4,399,209 and Japanese patent application Kokai Ser. No. 58-88739.
According to the conventional apparatus 300, there are provided a sheet roll cassette 305 for accommodating therein a non-exposed rolled microcapsule sheet 306 and a take up unit 307 for winding light-exposed microcapsule sheet. These sheet roll cassette or cartridge 305 and the take up unit 307 are disposed at lower positions of the apparatus. More specifically, an original (not shown) is mounted at an original support stand 303 which is covered with a cover member 302, and a light source 301 is disposed below the original support stand 303. A lens 304 is provided between the original support stand 303 and an exposure zone B. Furthermore, a developer sheet cassette 308 is disposed above the exposure zone B, so that each one of the developer sheet 309 is supplied onto the photosensitive sheet 306 at a pressure developing zone 311 by means of a supply roller 310, and is discharged by a discharge roller 312. Therefore, the microcapsule sheet 306 is always positioned below the exposure unit B, the optical components 301, 304, and the developer sheets and their associated components 308, 310.
According to such conventional apparatus, since the installing position of the microcapsule sheet is extremely low, it would be troublesome to take out the entirely light-exposed sheet 306 from the apparatus 300 and to newly assemble the rolled non-exposed microcapsule sheet into the apparatus.
Further, in the conventional apparatus, the sheet roll cassette 305 includes a cartridge shaft 14 engageable with cartridge support shafts 14A as shown in FIG. 2. The sheet roll 306 wound around the cartridge shaft 14 is subjected to a back-tension so as to prevent the sheet in the sheet path from being slackened. This back-tension is applied to the support shafts 14A. When the sheet cartridge 305 is intended to be disassembled from the apparatus, the cartridge support shafts 14A are moved away from the cartridge shaft 14, so that the latter is disengaged from the support shafts 14A. For conducting such movement of the support shafts 14A, a solenoid (not shown) is drivingly connected to the support shaft 14A. However, the employment of the solenoid also requires associated electrical circuit, to thus render the overall apparatus costly, and large noise may be generated during actuation of the solenoid for driving the support shafts 14A.